1. Field of the Invention
The present invention relates to a testing tool, and more particularly to a precision printed circuit board testing tool capable of testing a printed circuit board (PCB) circuit precisely to assure the quality of the PCB circuit before electronic component modules are inserted and assembled onto the PCB.
2. Description of the Related Art
After a conventional printed circuit board (PCB) is manufactured, the PCB usually goes through a testing procedure to test whether or not the printed circuit board is good. If a defective printed circuit board is not detected after electronic component modules are installed onto the defective printed circuit board, circuits on the PCB cannot operate, and thus incurring a loss to printed circuit board manufacturers. Obviously, the testing operation for printed circuit boards is very important. In a conventional printed circuit board testing tool as shown in FIG. 1, a plurality of testing bases 91 are disposed on a testing machine 90, and each testing base 91 includes a plurality of testing tubes 92 and a probe 93 is installed in each testing tube 92 and pressed against by a spring 94 in the testing tube 92 and protruded out from the testing base 91. Further, the probe 93 is electrically connected to a guidance wire 95 for connecting a voltmeter (not shown in the figure). When the conventional printed circuit board testing tool is used for testing, the probe 93 is contacted with a conductive pad 101 (PAD) of a printed circuit board 100 for testing whether a circuit between the two conductive pads 101 is an open circuit (OPEN) or a short circuit (SHORT) and with a micro resistance to determine if the printed circuit board 100 is a good product or a defect.
As we all know, the design of existing printed circuit boards tends to be complicated and precise. If a testing PCB circuit is of a low resistance or a micro resistance, the resistance of guidance wires and contacts used for testing become interferences and cannot be ignored, and thus the conventional printed circuit board testing tool using a 2-wire connection for testing resistance is not accurate or precise, and causing difficulties for accurately determining whether a printed circuit board is a good item or a defect. Obviously, the prior art demands immediate attentions and feasible solutions.
In view of the foregoing shortcomings of the prior art, the inventor of the present invention based on years of experience in the related industry to conduct extensive researches and experiments, and finally developed a precision printed circuit board testing tool with better accuracy and precision to overcome the shortcoming of the prior art.